VisualForce 1. SalesForce provides two ways to build user interfaces. These are Page Builder and VisualForce. PageBuilder automatically generates pages with default lookand-feel. VisualForce allows developers to define their own user interface.
2. VisualForce plays the role of JSP or ASP in SalesForce. It is used to develop user interface for SalesForce applications.
3. Standard tags are included in VisualForce using apex keyword. As an example the top level tag in VisualForce is <apex:page>.Rest of the code is included in <apex:page>. Custom tags use tags use the prefix c:.
4. The syntax to access fields in VisualForce is {!object.Field}. The expression in between {!} is evaluated. $User gives the details of the user that is logged in. {!$User.FirstName} displays the first name of the logged in user.
5. A VisualForce page contains HTML, VisualForce components, JavaScript, Flash and text. All elements need to be well-formed. Visual Force gets converted into HTML at the server.
6. VisualForce can be used to support other devices like phones, PDAs.
7.
generates an input element. Based upon the data type of account,name field, appropriate user interface element is displayed (such as text box, pick list). This is an example of data binding. The value of the name field is displayed in the user interface, and changes are saved back to the object. <apex:inputfield value="{!account.name}"/>
8.
<apex:form>
is used to display a form. Other VisualForce display elements like text box, checkbox are included in a form.
9.
<apex:detail/>
is used to print the details page for an object. If the attribute "relatedlist" is set to false, then related lists are not displayed. Specific related lists can be added using the VisualForce component <apex:relatedlist>
10. VisualForce supports development mode. Development mode can be enabled using Setup|My Personal Information}Personal Information. In development mode, VisualForce provides two main features. A. Split screen development: In this the browser window is divided into two parts. The bottom part is used to show VisualForce code. Changes can be saved and resulting page is displayed on the same browser window. B. Creation of new pages by just typing the URL www.servername.com/apex/PageName where servername is the SalesForce server that is allocated to you.
11. Page layouts support one or two columns. VisualForce can support more than two columns.
12. Previous version of VisualForce is S-controls. It is now being phased out. Visual force two advantages over S-control A. Visual force having much better performance as compared to S - control. B. Visual force is a tag Markup language and S - controls are a javascript procedural code language.
13. VisualForce components and pages have version numbers. SalesForce stores the version numbers along with pages. All older versions are supported.
14. VisualForce elements take attributes similar to XML format. As an example in the statement below, sidebars and top headers are not displayed. <apex:page showHeader="false"> </apex:page> <apex:page>
also takes an attribute renderAs as input which supports pdf
generation.
15. Record's id is sent via request parameter, and made available to the page. In the above example the id identifies the account for which name has to be displayed.
16. VisualForce consists of three type of elements A. VisualForce pages: These are used to define the user interface. VisualForce pages support multiple devices B. VisualForce components: Standard prebuilt or custom user interface components available through a tag library C. VisualForce controllers:<="" li="">
17. There are three type of controllers Standard Controller The standard controllers provide access to standard Salesforce.com behavior.<:apex:page standardController="Account"> They are available for all API entities/objects, such as Account, Contact, Opportunity etc as well as custom objects. They Provide access to standard Salesforce data and behavior Standard object record data and Standard actions like save, edit , delete. Custom Controller Custom Controllers is used for custom behavior or non-standard datasets.<:apex:page controller="MyAccount"> They can be used to create wizards or leverage call outs. Controller Extensions Controller Extensions extend the behavior of standard controllers.<:apex:page standardController="Contact" extensions="ClassA, ClassB"> They are used to add custom behaviour or additional data to controllers 18. Static resources are accessible through global variables $Resource. It can be used to access CSS stylesheets, images, flash movies and JavaScript libraries.
19. Error messages are displayed in pageMessages component and can be displayed by the statement <apex:pageMessages/>
20. To perform the save operation, the save() method can be invoked on the object. This is an example of action binding. <apex:commandButton value="Save" action={!save}"/>
21. The look-and-feel of VisualForce is managed using StyleSheets. Default SalesForce look-and-feel can be changed.
22. The size of VisualForce page cannot be more than 15MB.
23. Web Services can also be invoked from VisualForce.
Layout Editors
24. Layout editor provides a drag-and-drop interface to define the user interface. Using Layout editor, fields of a page can be moved around, sections and space can be added.
25. Layout editor supports one-column and two-column layout.
26. Double-clicking on a field allows fields to be made read-only and required.